Android Studio - Android development environment based on IntelliJ IDEA
Amazon Appstore - The Amazon Appstore is a place to purchase and download apps for your Android device.
Xcode - Xcode is Apple’s powerful integrated development environment for creating great apps for Mac, iPhone, and iPad. Xcode 4 includes the Xcode IDE, instruments, iOS Simulator, and the latest Mac OS X and iOS SDKs.
GetJar - Discover and play paid apps and games for free.
Firebase - Firebase is a cloud service designed to power real-time, collaborative applications for mobile and web.
F-Droid - F-Droid is an interesting alternative for Android users who want to try something different and not have to use the Goole Play store all the time.